超声波对微电解处理硝基苯的协同效应研究

以硝基苯为目标污染物,考察超声波对微电解技术的协同效应.结果表明,无机械搅拌条件下,硝基苯溶液初始质量浓度为50 mg·L~(-1)、超声波功率密度为200 W·L~(-1)、溶液初始pH值为3.0时,超声波/微电解协同体系降解效果显著高于超声波与微电解单独作用之和,降解过程超声波和微电解间存在显著协同效应,比较3者的降解速率常数可知超声波与微电解间的协同因子达4.875.研究表明,超声波能有效防止铁屑表面钝化和板结现象,超声波促进微电解体系中·OH生成是超声波对微电解降解硝基苯产生明显协同效应的主要原因.

Study on the synergistic effect of ultrasonic waves on the degradation of nitrobenzene through micro-electrolysis

In this paper, we have introduced our research results on the synergistic effects of the combination of ultrasonic waves and micro-electrolysis on the degradation of nitrobenzene. As is known, great interest of the researchers in the line has long been shown in the micro-electrolysis circle for its high efficiency, which is based on the electrochemical reaction between ferrum and carbon on the surface of the scap iron. However, since electrochemical reaction in any cases tends to be inactivated after long-time of operation, it is necessary to use ultrasonic waves to clean the surface effectively and make the fillings activated because of its cavitation effect. In addition, since ultrasonic waves possesses with the radicals, pyrolysis and supercritical water oxidation, which is beneficial for the organic pollutants degradation, the method here has thus been made rather popular. The results of our experiments have shown that the initial solution pH had great effect on the nitrobenzene degradation and the optimization of pH value can be made to be over 3.0 among the range of 3.0 to 9.0. Our experiments also show that the degradation rate of nitrobenzene tends to decrease with the increase of the initial concentration of nitrobenzene and increase with the increase of ultrasonic wave intensity. Without mechanical agitation, the synergistic effect can be made much greater than the sum of the two single treating in the condition of the initial nitrobenzene concentration being 50 mg·L~(-1), and the density of ultrasonic intensity-200 W·L~(-1), with the initial pH value of 3.0. Comparing the degradation rate constant of the three techniques, it can be found that there potentially lie significant synergetic advantages of ultrasonic and micro-electrolysis, which can be expected to reach the cofactor 4.875. The analysis shows that the principal advantage of the synergistic effect of ultrasonic wave power and the micro-electrolysis on nitrobenzene degradation lies in that it can effectively prevent the surface inactivation and hardening of the phenomena of the scrap iron and promote the formation of ·OH free radicals.